Air diffusing means



2 Sheets-Sheet A. C. DURDIN, JR AIR DIFFUSING MEANS Filed July 13, 1938 Nov. 12, 1940.

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A. c. DURDIN, JR f 2,221,346

AIR DIFFUSING MEANS Filed July 13, 1938 2 Sheets-Sheet 2 INVENTOR. I fl/yai/u: Qflurd/h, J:

ATTORNEY.

1 Patented Nov. 12,1940

UNITED STATES 2,221,346 Am DIFFUSING MEANS .gustus C. Durdin, .lr., Lincolnwood, Ill., assignor to Chicago Pump Company, Ghicago,-lll., a

corporation of Illinois Application July 13, 1938, Serial No. 219,099

Claim.

This invention relates to air diffusing means of that character intended principally for use in the aerating tanks of sewage treatment plants, and has reference more particularly to. that type of- 5 diffusing means which employ porous, hollow diffusers connected with a header for supplying air to the contents of the tank in whichthe diffusing means is employed.

Generally speaking, air under pressure is forced through a header which is disposed adjacent the bottom of the tank adjacent one wall thereof, to which header a great multiplicity of diffusers are attached and through the pores of which the air is forced into the surrounding liquid. Diffusers are composed of porous material and occasionally one breaks and when this occurs with the diffusers heretofore in use, great quantities of air are discharged from the broken diffuser thereby reducing the pressure in the header so that the diffusers do not supply the required amount of diifused air throughoutthetank.

One of the objects of the present invention is to provide means whereby when a diffuser breaks, the amount of air escaping therefrom is insignificant as compared with that escaping when the ordinary diffuser becomes broken. The pressure in the header is not materially reduced and, therefore, the proper functioning of the other diffusers is not interfered with. Furthermore, in case several diffusers become broken, the deficiency in pressure may be readily made up to the required pressure.

Headers are usually of great length, sometimes extending from 100 to 500 feet in length, and the desideratum is to have them supported in a level condition, and one of the objects of the present invention is to provide supports forthe headers having leveling means whereby the headers may be supported in a level condition. Another ob- ,ject is to provide means for anchoring the supports permanently'to the bottom of the tank.

With these and other objects and advantages in view, this invention consists in the several novel features hereinafter more fully set forth and claimed. r

The invention is clearly illustrated in the drawings accompanying this specification in which:

Fig. 1 is a vertical, longitudinal section taken through an aerating tank, partly broken away, and illustrating one embodiment of. the invention applied thereto.

Fig. 2 is an enlarged view partly in side elevation and partly in vertical, longitudinal section through a header and two diffusers, one partly form of diffuser.

broken away, the line of section being indicated at 2-2 in Fig. 1.

Fig. 3 is an end view'of a diffuser looking in the direction of the arrow 3 in Fig. 2.

Fig. 4 is an end elevation of the diffuser looking in the direction of the arrow 4 in Fig. 2.

Fig. 5 is, a vertical cross section taken on the line 5-5 of Fig. 2. Fig. 6 is a vertical cross line 5- 6 of Fig. 1. Fig. 7 is an enlarged view partly in elevation andpartly in cross section of one of the supports or standards and a-header, the .line of section being indicated at 1-l in Fig. 1.

Fig. 8 is an enlarged, fragmenta'l, vertical, longi- 15 tudinal section taken through a header and a modified form of the diffuser.

Fig. 9 is an end elevation of the diffuser seen in Fig. 8 looking in the direction ofthe arrow 9.

Fig. 10 isan end elevation of a second modified section taken on the Referring to said drawings and. first to Figs. 1 to '7 inclusive, the reference characters ill designate a series of aerating tanks usually composed of concrete and comprising a common bottom II from which rise longitudinally extending walls or partitions l2 which separate the tanks from each other. Fillets l3 maybe provided atthe corners of the tanks (see Fig. 5) to facilitate circulation of the tank contents thereinQm End walls l4, ii are provided at the ends of the tanks and an influent conduit or gutter i6 is provided at the top of the end Wall l8, and an effluent conduit 91 is provided at the top of the other end wall l5, which conduit is provided with 35 a weir l8- over which the tank contents overflows into the eiiiuent channel or gutter. At one end of the tanks is a passageway l9 formed between the end wall l4 and an outside wall 20.

Leading from a suitable air pump or compressor (not shown) is a main header 2| which extends through the passageway l9, and from said header 2| lead diffuser headers 22 which pass through the end walls H of the tanks adjacent 45 the bottoms thereof and extend along the lengths of the tanks adjacent one of the walls I2 thereof. Standards .or other supports23 are provided along the length of the diffuser headers for supporting them in a level condition. To maintain a substantially even pressure throughout the lengths of the diffuser headers, they are formed 'in sections steppeddown in diameter from the main header to the other end of the tanks. Flexible couplings 2 3 are provided between the adjacent to header sections to permit of slight misalignment thereof.

A trap 25 is interposed in each difluser header in the passageway l9, which trap collects foreign particles, oil and water that may find its way to the diffuser headers. A blow-oif pipe 26 leads from each trap 25 and is-provided with a valve zl'whereby when the valve is opened, the accumulated foreign matter may be blown out of the trap. 1 r

Ea'ch diffuser header is drilled and tapped at a great multiplicity of closely spaced places along its length on both sides to-provide discharge openings into which are screwed the adapters or connections of the difiusers 28, which project horizontally from the header on both sides thereof in parallel relation to each other.

The diffusers are of similar construction and a description of one will sumce for all.

Referring to Figs. 2 to inclusive, the diffuser will be seen to consist of a hollow body portion 29 desirably formed of carbon or other suitable porous material and in its preferred form the body portion is composed of an upper section 30 which is porous and a lower section 3! which is not required to be porous, the two sections being cemented or otherwise suitably fastened together. This shape of diffuser body is of the type known as the tear drop type. One end of the hollow body is closed by a head 32 'and upon the other end is an adapter 33 which is provided with a hexagonal or other noncircular part 34 for the reception of a wrench and a threaded stem 35. Desirably, gaskets 3B are interposed between the body 29 and the head 32 and adapter 33 to make tight joints therebetween,

and a rod 31 threadedly secured in the adapter 33 and provided with a nut 38 on its other end is employed for rigidly securing together the parts of the difiuser. A restricted duct 891 extends through the adapter from the hollow of the diffuser body to the end vides a restricted communication between the interior of the header and the hollow of the difstricted duct between the interior of the header I and the hollow of the diffuser, 'then -in case a -diiTuser becomes broken the. air can only escape in relatively small quantities from the header through the restricted orifice, with the result that the pressure in the header is not reduced materially, and, consequently, the functioning of the other diffusers is not materially interfered with.

, In the operation of thediffusing means, air under pressure is forced through theheaders to and through the restricted ducts into the hollows .of the diffusers, from which the air is forced through the porous walls thereof and escapes in minute particles into the liquid surrounding the diffusers, whereupon innumerable small -air bubbles are formed and the air is absorbed by the liquid. Furthermore, the liquid above the diffusers is lightened and thereby rises, causing a circulation of the liquid as indicated generally by the arrows in Fig. 6. 75

One of the standards for supporting the headof the stem 35 and proers is illustrated in detail in Fig. 'l and comprises a hollow conical base 40 having one or more filler openings 4| in its side wall and formed at its upper end with a threaded boss 42 in which is threadedly mounted a post 43 which is provided upon its upper end with a saddle 4d upon which the header rests. A stirrup 45 having threaded ends passing through the end portions of the saddle and provided with nuts it provide means 'for clamping the header down upon the saddle.

In assembling the header and standards, the latter are placed underneath the header and the posts are adjusted vertically so as to hold the header in level condition. During the assembling of the parts the standards may be shifted about to accommodate the header sections in case of any misalignment thereof and, after the parts have been placed in position, concrete t! is poured through the openings M in the bases in order to weight and to fasten them to the bottom of the tank.

In the modified form of the invention illustrated in Figs. 8 and 9, the duct 39 0f the adapter 33 may be of greater diameter than that illustrated in Fig. 2 and at its inlet end it is provided with a valve 48 desirably of the flap valve type hinged to the stem 3'5 at 49. In all other respects, the diffuser may be constructed in accordance with one illustrated in Fig. 2. In this case air under pressure flows past the flap valve into the duct 39 and passes into the hollow of the diffuser body. In case the diffuser becomes broken, the rush of air irom the header will cause the valve 48 to close or partially close, thereby entirely shutting off or at least restricting the flow of air through the duct 39? to a considerableextent so that only a minimum amount of air may be discharged from the header through the broken diffuser.

In Fig, 10. is illustrated a cylindrical form of diifuser 28 which is provided with an adapter 33 which may be of the restricted duct type illustratedin Fig. 2 or the valve type illustrated in Fig. 8. Thecylindrical wall of the body of the diffuser seen in Fig. 10 is composed of porous material as in the other forms, and in case it becomes broken, only a minimum amount of air may escape from the header at the broken diffuser.

It is to be understood that the term header which has been used throughout the specification and claims is intended to include any form of air conduit through which air is supplied to the diffusers. Furthermore, the supports for the headers may be carried from above or below the headers.

I claim as new and desire to secure by Letters Patent:

1. Air difiusing means, comprising in combination a header through which air is supplied under pressure, a horizontal porous diffuser tube, provided on one end with an adapter threadedly secured in said header and having a single restricted duct leading from the interior of the header to the hollow of the diffuser, whereby, whenever the diffuser is broken, a restricted amount of air is permitted to escape through the duct.

2. Air diffusing means comprising in combination a header through which air is supplied under pressure, a horizontal porous difiuser tube pro-. vided on one end with an adapter threadedly secured in said header and having a single duct leading from the interior oi the header to the hollow of the difluser, the cross-sectional area oi the duct being relatively small as compared with that oi the hollow of the difluser, whereby a restricted amount of air is permitted to escape from said duct whenever the diiiuser is broken.

3 Air diii'using means for diflusing air into a body of liquid, comprising. in combination a header through which air is supplied under pressure, and a horizontal porous difluser tube closed I at one end and having a threaded adapter secured thereto at its other end and threadedly secured to said header, there being a single, restricted air passage through the adapter between, the interior oi the header and the hollow of the diffuser, through which air is forced into the hollow of the diiluser, and out through the pores thereof into a body oi! liquid surrounding the difiuser, the

cross-sectional area of the restricted air passage being relatively small "as compared with that of the hollow of the diffuser, whereby, whenever the difluser is broken, a restricted amount or air is header, in parallel relationship ,irom both sides thereof, each difluser having a porous, hollow, elongated tubular body, closed at its-outer end and having an adapter secured to -its other end and forming a supporting connection between thedifluser tube and the header, there being a single restricted air' duct through the adapter extending between the header and difiusertube, whereby, whenever any diffuser is broken, a restricted amount or air is permitted to escape from the broken difluser without materially reducing the pressureinthe header.

5. The combination of a headerthrough which air is forced under pressure, a horizontal porous difluser tube closed at one end and means secured to the other endiorming a supporting connection between the difluser tube and header,

said means having a single restricted duct therein leading. from'the header to the diffuser tube whereby to restrict the escape; of air from the header, at the place where the difluser tubeis' secured thereto, whenever the difluser tube breaks.

AUGUSTUS C. DUB-DIN, JR. 

